* lib/generator.rb: A new library which converts an internal

iterator to an external iterator.

* lib/abbrev.rb: A new library which creates an abbreviation table
  from a list.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@4767 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/abbrev.rb

@@ -0,0 +1,65 @@
+#!/usr/bin/env ruby
+#
+# Copyright (c) 2001,2003 Akinori MUSHA <knu@iDaemons.org>
+#
+# All rights reserved.  You can redistribute and/or modify it under
+# the same terms as Ruby.
+#
+# $Idaemons: /home/cvs/rb/abbrev.rb,v 1.2 2001/05/30 09:37:45 knu Exp $
+# $RoughId: abbrev.rb,v 1.4 2003/10/14 19:45:42 knu Exp $
+# $Id$
+
+module Abbrev
+  def abbrev(words, pattern = nil)
+    table = {}
+    seen = Hash.new(0)
+
+    if pattern.is_a?(String)
+      pattern = /^#{Regexp.quote(pattern)}/	# regard as a prefix
+    end
+
+    words.each do |word|
+      next if (abbrev = word).empty?
+      while (len = abbrev.rindex(/[\w\W]\z/)) > 0
+	abbrev = word[0,len]
+
+	next if pattern && pattern !~ abbrev
+
+	case seen[abbrev] += 1
+	when 1
+	  table[abbrev] = word
+	when 2
+	  table.delete(abbrev)
+	else
+	  break
+	end
+      end
+    end
+
+    words.each do |word|
+      next if pattern && pattern !~ word
+
+      table[word] = word
+    end
+
+    table
+  end
+
+  module_function :abbrev
+end
+
+class Array
+  def abbrev(pattern = nil)
+    Abbrev::abbrev(self, pattern)
+  end
+end
+
+if $0 == __FILE__
+  while line = gets
+    hash = line.split.abbrev
+
+    hash.sort.each do |k, v|
+      puts "#{k} => #{v}"
+    end
+  end
+end